Switch structure



De.17,194. B ESHAW 2,225,236

swITcH STRUCTURE Filed Feb'. 27, 1959 Patented Dec. 17, 14940y UNITED STATES PATENT OFFICE 2,225,236 SWITCH STRUCTURE Burton E. Shaw, Bristol, Ind., assigner to Penn Electric Switch Co., G of Iowa l oshen, Ind., a corporation Application February 21, 1939, serial No'. 258,707

s claims. (ci. zoo-s3) rotatable rod or adjusting screw, a control knob being provided for the rod and the two being normally so associated that they rotate together.

The rod is capable of longitudinal movement relative to the knob whereupon the knob and rod may be relatively rotated so that the rod then has a new position relative to the knob.

A further object of my invention is to provide the knob of hollow construction and the rod with ,20 a head located within and thereby concealed by the knob, the knob having an internal socket to receive the head of the screw and an adjusting spring adjusted by rotation of the rod and normally tending to keep the head seated within the socket.

Still another Objectis to provide for adjustment of the rod relative to the knob by permitting longitudinal movement of the roel for unseating the head -from the socket whereupon the knob androd may be relatively adjusted and thereafter will operate through a different range as the knob is rotated from one of its limits of movement to the other. I

Still a further object is to provide the` knob formed of a washer with a socket stamped therein and a cup-like stamping pressed over the edge of the washer for inexpensively assembling the two relative to each other after the range adjusting screw is associated with the washer and cup-like member.

With these and other objects in view my invention consists in the construction, arrange- Vment and combination of the various parts of v my device, whereby the objects contemplated 49 are attained, as hereinafter more fully set forth,

pointed out in my claims and illustrated in the accompanyingv drawing. Although the invention is susceptible of a variety of embodiments, .it is unnecessary to fully describe and illustrate more than one in order to give a full understanding of the invention both from its structural and functional standpoints. Accordingly,

I have illustrated a preferred and desirable embodiment of the invention in the accompanying drawing, in which:

Figure l is a front elevation of a-switch structure embodying my invention, the cover plate therefor being removed and a portion of a bellows housing being shown in section.

Figure 2 is a sectional view on -theline 2 2 gf 5 Figure 1 showing parts of the structure partly omitted.

Figure 3 is an exploded perspective view of the essential elements of my invention; and

Figure 4 is an enlarged sectional view similar 10 to the upper left hand portion of Figure 2 showing the parts in position for securing auxiliary adjustment of the -type peculiarly possible with my structure.

On the accompanying drawing, I have used the 15 reference numeral I0 to indicate generally a switch housing. Within the switch housing I0 I provide a switch mechanism consisting of a supporting bar I2, stationary contacts I3 and movable contactslI4. The contacts I4 are car- 20 ried by an armature I5. The armature I5 is pivoted at I6 to a bracket Il and coacts with a permanent magnet I8 to effect snap action of the switch contacts.

For automatically controlling the armature I5 -25 I provide a bell crank lever I9 pivoted at 20 to a bracket 2I and a bellows 22. The lever I9 is operatively connected to the armature I5 by a leaf spring 23 and link elements 24 and 25. The bellows 22 is contained in a housing 26 whereby 30 the bellows is responsive to variations in pressure in the housing as produced in a tube 21 connected with the housing. Any pressure changing means may be connected with the tube 21, such as a temperature responsive capillary 35.

bulb 28 in which case the tubeA and bulb will be charged with the proper gas or liquid to secure the desired operation in the temperature range for which the switch is designed'.

An operative connection is provided between 40 the bellows 22 and the lever I9 through the medium of a thrust pin 29 connected with the head of the bellows and bearing against the bellows. A range spring 30 maintains such engagement. 45

The tension of thespring 30 is made adjustable in response to various positions of rotation of a rod 3I. The rod 3| is threaded at 32 and these threads coact with a threaded bore of a plug 33.

'I'he plug 33 is received in the upper' end of the 50 washer W whereby the knob and washer are held assembled by friction. Above the washer W there is provided a head 33 adapted to seat in a socket 31 of the washer W. A knob K is positioned over the head 33 and is a press-fit on they periphery of the washer W.

The knob K is inverted cup-like in character having a top wall 38 and a cylindrical wall 39. The depth of the knob K is such that the head 36 of the rod 3l may be left out of the socket 31 of the washer W as shown in Figure 4 whereupon the head and washer may be relatively adjusted rotationally. The socket 31 is of such shape that when the head 36 is seated therein the rod 3| will rotate simultaneously with the knob and washer.

The washer W may be inexpensively made as a stamping with the socket 31 stamped therein and resulting in the formation of a hub I0 on the lower surface of the washer to engage the casing I0 and thereby space the major portion of the lower face of the washer from the casing. The knob K is limited to less than 360 rotation by a projection Il therefrom to engage a stop projection 42 struck upwardly from the casing I0.

Practical operation The manufacture and assembly of my switch structure are comparatively simple. The rod 3| is which would increase the cost considerably. The elements W and K can be manufactured in great quantities as they may be stamped out. The assembly of the knob K on the washer W is a simple press operation eliminating all set screws or other fastening means or welding operations. The stop 42 is easily struck'up from the sheet metal casing I0 thus eliminating the making of a pin, the drilling of a hole and the mounting of the pin in the hole as in usual constructions.

All these features make for economy in manufacture and assembly.

The range of the switch can be adjusted at the factory by utilizing. a pair of pliers or suitable 45 tool to engag the rod 3l and lift it against the constraint of the spring 30 and then rotating the knob K to a new position relative to the rod 3l, if the change in adjustment is to be less than that represented by a full'rotation of the knob K. If several revolutions of the knob K are to be made, the knob can be lifted with the screw so that the stop elements 4| and 42 do not engage with each other.

By a combination of the two methods just de,- scribed, the switch can be preset -for operation 'within a given range of adjustment as required by any desired installation. After the switch is installed it can be adjusted by the user throughout the range of rotation of the knob K as determined by the stops 4l and 42, but the manner of adjusting the parts illustrated in Figure 4 is not obvious to the user because the head 36 and the socket 31 are concealed within the knob and the washer. A serviceman knowing the construction of the switch however can at any time change the adjustment thereof so that the knob Kthereafter throughout its range of movement will secure a new rangeof operation for the switch.

The variations in such auxiliary adjustment may be made as fine as 1/12 of a revolution due to the relative shapes of the head 36 and the socket 31 as illustrated in Figure 3.

In accordance with theprovisions of the patent statutes I have described and illustrated one form of my switch structure and have also disa standard bolt instead of being made specially,.

closed the principle of operation thereof. I consider the form shown in the drawingto represent one of the best embodiments of the invention but desire it to be understood that the structure disclosed is only illustrative and that the invention may be carried out by other means within the scope of the appended claims.

I claim as new and desire to secure by Letters Patent:

1. In a switch structure, switch mechanism, condition responsive means for operating said switch mechanism in response to variations in a condition to which said condition i vresponsive means responds and means for adjusting the range of operation of said switch structure comprising a range spring, an adjusting screw therefor, a hollow knob having limited rotation, said adjusting screw having a head enclosed within said knob, said head being other than round, said knob having an other than round socket therein in which said head is normally seated, said head being unseatable from saidsocket by longitudinal movement of the screw against the constraint of said range spring and thereafter rotatable relative to the knob to a new position relative to said socket.

2. In a controldevice, control mechanism, con-- dition responsive means operatively connected therewith to change the position thereof in response to variations in the condition to which said condition responsive means responds, rotatable adjusting rod and a spring effective to modify the operation of said control device in different positions of rotation of said rod, a hollow knob for effecting rotation of said rod, said rod having a head within said knob, said knob having a socket to receive said head and Ieilect rotation of the head with the knob, said spring serving to normally retain said head seated in said socket, said rod being movable longitudinally to disengage said head from said socket against the constraint of said spring whereupon said knob is rotatable to a new position relative to said rod with said spring thereafter reseating said head in said socket upon release of the rod.

3. In a control device of the character described, control mechanism, a casing therefor, condition responsive means operatively connected with said control mechanism to change the position thereof in response to variations in a condition, an adjusting rod effective to modify the operation of said control device in different positions of rotation of said rod, a head on said rod, a washer under said head and having asocket to receive the head and prevent relative rotation of the rod and washer, an inverted lcup-like knob positioned over said head and connectedf'with the periphery of said washer whereby said washer and knob completely enclose said head, the space in said cuplike knob beyond the end of said head being in excess of the depth of thesocket whereby to permit longitudinal movement of said rod to a position with said head out of said socket to permit rotation of said head relative to said washer, said washer having a hub on the .lower surface thereof, the casing of the switch having a projection and said knob having a projection to coact therewith to limit the rotation of said knob and washer.

4. In a control device of the character described, control mechanism, condition responsive means operatively connected therewith to change the position of the control mechanism in response to variations in the condition affecting said condition responsive means, an adjusting rod effective to modify the operation of said control device in different positions of rotation of'said rod, a

head on said rod, a washer under head and having a socket to receive the head and prevent relative rotation of the rod and washer. a hollow knob positioned over said head and connected with the periphery oi said washer whereby said washer and knob completely enclose said head, said head being capable of movement to a position out of said socket to permit rotation of said head relative to said washer and means to limit the rotation of said knob and washer.

5. In a control device, control mechanism, a condition responsive device operatively connected therewith to change the position of the control mechanism in response to changes in the condi- -in said hollow knob beyond beine in excess of the depth of said socket whereby to permit longitudinal movement of said element to a position with said means out of said socket to permit rotation of said element relative to said washer and knob.4

6. In a control device of the character de.

scribed, a casing, control mechanism therein, condition responsive means operatively connected therewithto operate the control mechanism, an adjusting rod extending through a wall of said casing and effective to modify the operation of said control device in different positions of rotation of said rod, a head. on said rod, a washer under said head and having a socket to receive the head andprevent relative rotation of the rod and washer, an inverted cup-like knob positioned over said head and connected with the periphery of said washer, the space in said cup-like knob beyond the end of said head being in excess of the depth of said socket whereby to permit longitudinal movement of said rod to a position with said head out of said socket to permit rotation of said head relative to said washer, said knob having a projection and said casing having a projection struck up therefrom to coastv with said" projection oi' said knob and limit its rotation.

BURTON E. SHAW. 

